PFAS: Per- and Polyfluoroalkyl Substances

Per- and polyfluoroalkyl substances (PFAS) are a group of more than 14,000 human-made substances (U.S. EPA CompTox) that are not naturally occurring and are resistant to heat, water, and oil. Due to their unique chemistry, PFAS have been widely used as surface coatings and protectant formulations in consumer, commercial, and industrial products such as carpet, home textiles, clothing, food packaging, and non-stick cookware. PFAS have also been used for industrial applications, such as a surfactant in chrome plating and for emergency response applications, such as in firefighting foam. In typical conditions, PFAS are resistant to degradation and do not break down in the environment.

Exposure to PFAS may result in adverse health effects including developmental effects to fetuses during pregnancy, cancer, liver effects, immune effects, thyroid effects, and other effects (such as cholesterol changes). In several national studies, PFAS have been found in the blood serum of nearly all people tested.

Exposure and Occurrence

PFAS has been detected in air, water, wastewater, fish, and soil worldwide. PFAS are especially present in and around manufacturing facilities that use or produce PFAS. Some PFAS are volatile and can be carried long distances through the air. PFAS have been detected in many parts of the world, including oceans and the Arctic, indicating that long-range transport is possible.

People can be exposed to PFAS through food, food packaging, consumer products, house dust, and drinking water. Four major sources of PFAS in drinking water are fire training and response sites; industrial sites; landfills; and wastewater treatment plants and biosolids. Once in groundwater, PFAS can be easily transported large distances, tend to accumulate in groundwater, and can contaminate sources of drinking water. Contaminated drinking water has led to high levels of exposure to PFAS for some populations residing near manufacturing facilities that use or have used PFAS in their manufacturing process.

More information about PFAS in non-drinking water, monitoring/occurrence maps, and other actions in California addressing PFAS can be found at the State Water Board’s PFAS web portal.

PFAS Regulations for California Drinking Water

Public Health Goals and Maximum Contaminant Levels

On April 10, 2024, the United States Environmental Protection Agency (U.S. EPA) announced final National Primary Drinking Water Regulation (NPDWR) for six PFAS, establishing legally enforceable Maximum Contaminant Levels (MCLs). The PFAS compounds PFOA, PFOS, PFHxS, PFNA, HFPO-DA (commonly known as GenX) are regulated as contaminants with individual MCLs. The PFAS compounds PFHxS, PFNA, PFBS, and HFPO-DA (GenX) are regulated as a PFAS mixture with a Hazard Index (HI) MCL. The regulation proposed by U.S. EPA will require public water systems to monitor for these PFAS, notify the public of the levels of these PFAS, and reduce the levels of these PFAS in drinking water if they exceed the standards.

The Hazard Index is made up of a sum of fractions. Each fraction compares the level of each PFAS measured in the water to the highest level below which there is no risk of health effects. The Hazard Index MCL is set at 1 and applies to any mixture containing two or more of PFHxS, PFNA, PFBS, and HFPO-DA (GenX) is set at 1. For more information on the Hazard Index MCL, see U.S. EPA's Hazard Index MCL fact sheet.

The timeline for rule implementation provided by U.S. EPA is as follows:

• Within three years of rule promulgation (2024 - 2027):
  • Initial monitoring must be complete
• Starting three years following rule promulgation (2027 - 2029):
  • Results of initial monitoring must be included in Consumer Confidence Reports (i.e., Annual Water Quality Report)
  • Regular monitoring for compliance must begin, and results of compliance monitoring must be included in Consumer Confidence Reports
  • Public notification for monitoring and testing violations
• Starting five years following rule promulgation (starting 2029):
  • Comply with all MCLs
  • Public notification for MCL violations

For further information about this regulation and resources for both the general public and public water systems (including fact sheets, frequently asked questions, and communications toolkits), please see U.S. EPA's webpage for the Final PFAS National Primary Drinking Water Regulation.

For California, the development of standards for PFOA, PFOS, PFHxS, PFNA, HFPO-DA (GenX), PFBS, and other PFAS are among the priorities of the Division of Drinking Water. Updates to the rulemaking process for PFAS in California will be posted at the PFAS MCL rulemaking record webpage.

On April 5, 2024, the Office of Environmental Health and Hazard Assessment (OEHHA) adopted Public Health Goals (PHGs) for two PFAS: PFOA and PFOS. The PHG for PFOA is 0.007 nanograms per liter (ng/L) or parts per trillion (ppt). The PHG for PFOS is 1 ng/L or ppt. PHGs are established by OEHHA and are concentration of drinking water contaminants that pose no significant health risk, based on current risk assessment principles, practices, and methods. OEHHA establishes PHGs pursuant to HSC §116365(c) for contaminants with MCLs, and for those for which MCLs will be adopted. HSC §116365(a) requires a contaminant's MCL to be established at a level as close to its' PHG as is technologically and economically feasible, placing primary emphasis on the protection of public health. In this way, PHGs serve as the basis for the development of MCLs. In addition to the PHGs for PFOA and PFOS, the Division of Drinking Water has also requested that OEHHA include evaluations as to evaluate whether PFAS can be grouped together for regulatory purposes or based on specific characteristics or features of the chemicals.

Notification and Response Levels

Notification levels (NLs) are nonregulatory, health-based advisory levels established for contaminants in drinking water for which MCLs have not been established. NLs are established as precautionary measures for contaminants that may be considered candidates for establishment of MCLs but have not yet undergone or completed the regulatory standard setting process prescribed for the development of MCLs and are not drinking water standards. NLs represent the concentration level of a contaminant in drinking water that does not pose a significant health risk but warrants notification. NLs are issued by the Division of Drinking Water and developed based on recommendations made by the OEHHA.

A response level (RL) is set higher than an NL and represents a recommended chemical concentration level at which water systems consider taking a water source out of service or provide treatment if that option is available to them. Starting in January 2020, water systems that receive a monitoring order and detect levels of PFAS substances that exceed the RL shall take a water source out of use, treat the water delivered, or provide public notification.

When chemicals are found at concentrations greater than their NL and/or RL, certain requirements and recommendations apply. Statutory requirements for public notification are contained in HSC §116455. PFAS with NLs and RLs have additional requirements per HSC §116378. Further information can be found at the Notification and Response Levels webpage. Below is a summary of PFAS NLs and RLs issued, requested, or proposed.

PFAS Monitoring and Results for Drinking Water

Fifth Unregulated Contaminant Monitoring Rule (UCMR5)

On December 27, 2021, U.S. EPA published UCMR5 to Title 40 of the Federal Register (40 CFR, Part 141). UCMR5 requires public water systems to perform sample collection and analysis for 30 chemical contaminants (29 PFAS and lithium) between January 2023 and December 2025. The goal of UCMR5 is to provide scientifically valid data on the national occurrence of these contaminants in drinking water. All public water systems serving more than 10,000 people (i.e., large systems) will monitor; all public water systems serving 3,300 to 10,000 people; and a representative sample of 800 randomly selected public water systems serving fewer than 3,300 people will monitor pursuant to UCMR5. U.S. EPA is responsible for all analytical costs associated with UCMR5 compliance at systems serving fewer than 10,000 people.

Sample analysis is required to be performed by laboratories approved by U.S. EPA for UCMR5. A list of laboratories approved for UCMR5 can be found on U.S. EPA's website. The analytical methods to be used for UCMR5 PFAS analysis are EPA Method 533 and EPA Method 537.1. UCMR5 contains all 29 PFAS that are within the scope of EPA Method 533 and EPA Method 537.1.

Sample collection and analysis began January 2023. When available, data collected for UCMR5 will be hosted at the UCMR Occurrence Data Webpage on U.S. EPA's website. All systems that monitor under UCMR5 are required to notify their customers of the availability of UCMR5 results no later than 12 months after results are known. Community water systems are also required to report UCMR5 results at or above the minimum reporting level in their annual Consumer Confidence Report (CCR). For more information regarding UCMR5 including an overview fact sheet, the list of contaminants, minimum reporting levels, rule text, reporting requirements: US EPA’s UCMR5 Webpage.

Division of Drinking Water General Monitoring Orders

Assembly Bill 756 (2019-Garcia), approved by the Governor on July 31, 2019, and codified as HSC §116378, authorizes the State Water Board to issue orders requiring public water systems to monitor for PFAS. Since 2020, the Division of Drinking Water has issued several general monitoring orders to public water systems in California. It is required by HSC §116378 that if monitoring results in a confirmed detection, then a water system must report that detection in the annual Consumer Confidence Report (CCR). Additional requirements and information regarding PFAS general orders issued by the Division of Drinking water can be found at the PFAS DDW General Order webpage.

On March 4, 2024, The Division of Drinking Water issued General Order DW-2024-0002-DDW pursuant to HSC §116378. More information including order text, list of systems/sources for monitoring, and analyte list can be found at the PFAS DDW General Order webpage.

On October 31, 2022, The Division of Drinking Water issued General Order DW-2022-0001-DDW pursuant to HSC §116378 for the monitoring of 25 PFAS at drinking water system sources that are at risk for potential contamination by PFAS due to proximity with other water sources known to have confirmed PFAS detections. The order was issued for 1,296 sources belonging to 384 public water systems. Sample collection and analysis is to be conducted quarterly, beginning with the first calendar quarter of 2023, and continuing until further notice. Sample analysis is to be performed using EPA Method 533. Public water systems ordered to monitor under DW-2022-0001-DDW received or will receive direct communication regarding their compliance. No action is required of public water systems that did not receive direct communication regarding the order or were not named in the order. More information including order text, list of systems/sources for monitoring, and analyte list can be found at the PFAS DDW General Order webpage.

The Division of Drinking Water has issued PFAS General Monitoring Orders on two previous occasions: General Order DW-2021-0001-DDW and General Order DW-2020-0003-DDW. The monitoring for those orders is complete, and the orders have since been rescinded. For more information, see the PFAS DDW General Order webpage.

On March 2019, the Division of Drinking Water issued HSC §116400 Orders to 600 water system sites. Nearly 250 locations in the vicinity of airports with fire training and response areas, and municipal solid waste landfills are being reported to the State Water Boards for four consecutive quarters. Resulting dataset of this monitoring can be found at this file: pfas_monitoring_Q1Q2Q3Q4.xlsx.

Third Unregulated Contaminant Monitoring Rule (UCMR3)

On May 2, 2012, U.S. EPA published UCMR3 to the Federal Register (40 CFR, Parts 141 and 142). UCMR3 required the sample collection and analysis of 30 drinking water contaminants, six of which were PFAS, between January 2013 and December 2015. All public water systems serving more than 10,000 people and a representative sample of 800 public water systems serving 10,000 or fewer people were subject to monitoring for 21 List 1 contaminants, including the 6 PFAS contaminates, pursuant to UCMR3. Sample analysis was conducted using EPA Method 537, Rev. 1.1 by EPA approved laboratories. At that time, the lowest concentration minimum reporting levels established by U.S. EPA for PFOS and PFOA were 6.5 ng/L and 5.1 ng/L, respectively.

Monitoring under UCMR3 is complete and all results have been published. No action regarding UCMR3 is required of public water systems at this time. The resulting data is hosted at the UCMR Occurrence Data Webpage on U.S. EPA's website. A summary of UCMR3 results for PFOA PFOS and PFOA in California can be found at this file: UCMR3_CA_Summary_Data_for_PFOS_and_PFOA.xlsx

For more information regarding UCMR3 including an overview fact sheet, the list of contaminants, minimum reporting levels, rule text, reporting requirements: US EPA’s UCMR3 Webpage.

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